This invention relates to thin absorbent panty liners for protecting the wearer's undergarment both during intermenstrual use and, alone or in conjunction with other catamenial devices, during menstrual use.
Several products are now on the market to provide the user with protection from the staining of undergarments and, in general, are designed to be worn in the crotch portion of an undergarment. These products comprise a body facing side, pervious to body fluids; an absorbent body which is capable of absorbing and retaining quantities of body fluid and a fluid impermeable backing on the garment facing side of the product for preventing the fluid absorbed and retained from "striking through" onto the crotch surface of the undergarment. Additionally, these products have generally been provided with a layer of pressure-sensitive adhesive for adhering the product to the crotch portion of the garment.
One such product has been described in our co-pending U.S. patent application Ser. No. 423,389 filed on Sept. 24, 1982 which product has the added feature of breathability. As disclosed in the specification of this application, the panty liner described is required to hold relatively little fluid when used intermenstrually or when used in conjunction with other catamenial devices. However, as such product is meant to be worn for a considerable length of time, it is desirable that the product be capable of drying between fluid deposits. As described in the above-referenced disclosure, this is accomplished by designing the product to have a repellent, air permeable barrier on the garment facing side in conjunction with maintaining overall air permeability of the product to at least a minimum value. While "breathable" barriers have been known and suggested, this product was the first to be designed to provide overall breathability, in that the importance of this parameter, in products of this nature, is believed to have been recognized by the inventors for the first time.
The above-described product has performed efficiently when the use conditions for which it was designed occur, i.e., low volume deposits of body fluids. Unfortunately, on occasion the wearer experiences an unusually large discharge of fluid concentrated in a rather small area of the panty liner. In these instances, the panty liner fails to perform its function in that such fluid deposits pass directly from the body facing side of the permeable cover, through the absorbent layer and then through the breathable barrier and onto the undergarment.
There is therefore, a need to address this problem of strike through under unusually large deposition conditions, without sacrificing the other desirable aspects of the breathable panty liner.